Operational Modes - Scotsman CS0415 Service Manual

Operational Modes:

There are four main operational modes for the ice
maker:
•
Freeze
•
Harvest
•
Clean
•
Service (Diagnostics)
Ice Making Cycle
In addition, there are three possible "Off" cycles for
the ice maker. They occur when:
1. The bin is full of ice and the LED is illuminated
"ON/OFF" (Idle mode).
2. The "On/OFF" control switch has been held for
three seconds. The ON/OFF LED will go out.
Electrical System
Line Voltage is supplied to the electrical control
switches and the primary side of the step-down
dual transformer. The dual transformer reduces
120 VAC to 8.75 VAC for the cutter grid and the
bin light and 12 VAC for the drain and
recirculating pumps. The electronic control board
directs 12 VAC to the water recirculating and
reservoir drain pumps, and 120 VAC to the hot gas
solenoid, condenser fan motor, and compressor.
The measured fill water valve will always have 120
VAC on the BK and WH wires and 14 VDC on the
OR/WH and BK/RD wires.
An evaporator thermistor supplies temperature
information to the electronic control to determine
when to terminate the harvest cycle.
Refrigeration System
The hot gas refrigerant, under high pressure, is
forced through the condenser, where it changes
into a liquid, and flows through the drier and
capillary tube into the evaporator. Under low
pressure in the evaporator, the liquid refrigerant
absorbs heat from the water flowing over the
evaporator as the refrigerant evaporates into a gas.
As a low pressure gas, the refrigerant flows back
through the suction line of the heat exchanger, to
the compressor.
During the Freeze mode, some of the hot gas that
is in the condenser accumulating tube, condenses
to a liquid, and remains in the accumulating tube.
During the later stages of the Freeze mode, as the
ice slab forms on the evaporator freezing plate,
some of the refrigerant passing through the
evaporator will not evaporate into a gas, but will
remain a liquid. This liquid refrigerant will settle in
the accumulator, while the refrigerant vapor is
sucked off through the suction tube at the top of the
accumulator. This accumulated liquid refrigerant
will eventually be directed to the evaporator to
quickly warm the evaporator plate during the
Harvest mode.
Note: It is very important that the accumulator is
not tilted out of a horizontal position. If moved, it
could cause compressor failure.
Water System
The water recirculating pump moves the water from
the reservoir pan up to the distributor, where it
flows out over the evaporator freezing plate.
Water that does not freeze on the evaporator plate
runs off the front edge, and falls back into the
reservoir, where it is recirculated back to the water
distributor.
As the ice slab forms, the minerals in the water are
on the surface of the ice. The water
the top of the ice slab washes these minerals back
into the water reservoir pan. The water continues to
recirculate until the water level in the reservoir
drops to the bottom of the water level sensor.
When the water level in the reservoir drops below
the sensor, the control terminates the freeze mode
and initiates the harvest mode.
The control signals the measured fill valve to
the selected water level setting. The measured fill
valve uses a flow meter to accurately fill to the
correct volume.
•
Thin Ice uses 32 ounces (954cc),
•
Normal Ice 37 ounces (1106cc), and
•
Thick Ice 42.5 ounces (1258cc).
July 2007
Page 7
CS0415
Service Manual
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